Fuel control mechanism



5, 1958 c. H. FRICK 2,845,915

FUEL CONTROL MECHANISM Filed May 31, 1955 2 Sheets-Sheet 1 was j; Y AQQ/51/ 6,, EA E 52 INVENTOR.

ATTORNEY 5, 1958 c. H. FRICK 2,845,915

FUEL CONTROL MECHAILIISM Filed May 51, 1955 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY anism for an internal i aten Patented Aug. 5, 1958 2,845,915FUEL CONTRGL MECHANISM Charles H. Friek, Pontiac, Mich assignor toGeneral Motors Corporation, Detroit, Witch, a corporation of DelawareApplication May 31, 1955, Serial No. 511,924 14 Claims. or. 123-440 Thisinvention relates generally to a fuel control mechcombustion engine, andmore partrcularly to a fuel control mechanism for a fuel injection typeengine.

In internal combustion engines of the fuel injection type, the mixing ofthe fuel and air charges generally occurs in the combustion space withinthe individual engine cylinders, and the manually operable throttlecontrols are directly operable on the fuel supply control mechanism ofthe engine within speed limits established by the engine governormechanism. During periods of engine acceleration, this permits theengine such low speeds is relatively inefiicient compared to the mixingwhich occurs atthe higher engine speeds. Consequently, such operationresults in a concentration of relatively overrich fuel-air mixturewithin the portions of the individual engine cylinder combustionchambers adjacent the fuel injectors. These concentrations of overrichmixture burn relatively inefficiently with resultant fuel loss, carbondeposits, progressive operational deterioration, increased maintenance,and excessive exhaust smoking.

To the layman, the results of such operation are observable in the formof exhaust smoke puffs which emit from rapidly accelerating dieselpowered vehicles such as transit buses when the operator floors theaccelerator control pedal after each stop as he races to maintain atight schedule. mospheric conditions which are conducive to theaccumulation of smog, this operational feature of diesel engines hasresulted in local legislation bringing such engines within the purviewof local smoke prevention measures. As a'result of such legislation, ithas generally been found necessary to utilize exhaust scrubbers whichare relatively expensive and difllcult to mount and maintain in existingvehicles. The invention contemplates a simple mechanism adaptable to allexisting engines and effective to eliminate this smoking problem.

It is therefore a primary object of the invention to provide an enginefuel supply control mechanism with means for preventing full throttleengine operation at relatively low engine speed.

A further object of the invention is to provide an engine fuel supplycontrol mechanismwith means which will permit relatively rapid initialfuel-increasing response followed by a period of retarded advance of thefuel control mechanism to its full' throttle fuel-supplying operativecondition when a manually operable fuel control of the engine isadvanced rapidly from idle to full throttle position while the engine isoperating at relatively low speeds.

In accordance with the invention, the foregoing objects are achieved byproviding a fuel injection control mechanism with a fluid dashpotmechanism which is In certain areas having particular atoperable toretard the rotation of an injector control tube and the movement of fuelsupply controlling injector racks connected thereto to thereby controlthe fuel input to the engine from idle to full throttle position when anaccelerator control is rapidly actuated while the engine is operating atrelatively low speeds. The fluid dashpot mechanism is so constructed andarranged as to permit an initial period of relatively rapid advance ofthe injector control tube to provide a relatively rapid initial increaseof the fuel supplied to the engine followed by a period of retardedadvance between an intermediate and the full throttle fuel-supplyingoperative positions of the control tube and racks. Such operationpermits the engine to have desirable low-speed accelerationcharacteristics while the subsequent period of retardation obtained bythe use of the fluid dashpot mechanism prevents the concentrations ofoverrich mixture which normally occur from full throttle engineoperation at relatively low engine speeds as discussed above.

The foregoing and other objects, advantages and features of theinvention will be more thoroughly understood from the followingdescription of a preferred embodiment thereof in which reference is madeto the attached drawings, in which:

Figure l is a transverse sectional view of a portion of an engineshowing the preferred embodiment of the invention;

Figure 2 is a top elevational view of a portion of the engine shown inFigure 1;

Figure 3 is a fragmentary sectional view taken sub.

stantially on the line 33 of Figure'2; Figure 4 is a fragmentarysectional stantially on the line 44 of Figure 2;'and

Figure 5 is a sectional view taken substantially on the line 55 ofFigure 2.

Referring more particularly to the drawings, Figures and 2 show anengine cylinder head 10 having unit injectors 12, only one of which isshown, mounted Each injector has a plunger 14 operable toon a shaft 20between two rocker arms 22 and 24 which are operable to actuate theengine valves. The rocker arm shaft 20 is supported above the cylinderhead by suitable brackets 26 and 28 spaced longitudinally of thecylinder head.

Each of the unit injectors 12 is provided with control rack 30 which isreciprocable transversely of the engine to control the quantity of fuelsupplied to the engine cylinder by each stroke of the injector pluiger14. One end of each injector rack is pivotally connected to a lever 32which is adjustably secured to a common control tube 34 extendinglongitudinally of the 'engine. The control tube 34 is rotatablyjournaled in suitable mounting brackets 36, only one of which is shown.A

lever 38 secured to one end of the tube 34' is pivotallyconnected to oneend of an actuating link member 40. The opposite end of the link 40 isconnected to suitable throttle control linkages (not shown) of alimiting speed governor 44 similar to that shown and described in UnitedStates Patent 2,270,100, Centrifugal Governor, and issued to H. G. Adlerand J. C. Evans. nor linkages are in turn connected to the manuallyoperable accelerator control lever 46. 1

In accordance with the invention, the means providing for retarding thefuel-increasing rotation of the injector control tube and consequentlythe movement of the injector racks connected thereto comprises a dashpotmechanism '50 including a lever 48 which is adjustably secured viewtaken sub The gover- 3 at one end to the control tube. The distal end ofthe lever 48 is pivotally connected to one end of a link 52, theopposite end of which is pivotally connected to a piston 54. The piston54 is reciprocably mounted in a dashpot cylinder 56 formed integrally ofthe rocker arm mounting bracket 23. The bracket 28 is provided with alubricant supply passage 58 which is connected to the engine lubricantpressure supply through the passage 60 formed in the engine cylinderhead 10. A portion of the supplied lubricant is bled from the passage 53through an adjustable orifice or valve 62 to a cup formed in themounting bracket 28 above the cylinder. The cup 64 is connected to thecylinder by a hole or port 66 formed intermediate the ends of thecylinder and controllable by the piston 54. The head end of the dashpotcylinder 56 is provided with a restricted orifice 68 and a one-wayspring-biased check valve 70.

As best seen in Figure 5, the fuel control actuating link 40 between thegovernor and the control tube assembly includes a sleeve 72 embraceablysecured to a rod 74 at the governor-connected end thereof. At itsopposite end, the sleeve 72 is beaded inwardly to mount a bushing 76reciprocably mounting a reduced diameter center portion of a second rod78- having a plunger portion 86 reciprocably mounted within the sleeveand adapted to be pivotally connected at its opposite end to the controltube actuating lever 38. A helical spring 82 is interposed between theplunger 80 and the end of the sleeve mounting the rod 74 and tends tomaintain the plunger 80 in abutment with the stop formed by the bushing76.

In operation when the engine is running, a portion of the oil beingdelivered by the passage 58 for the lubrication of the rocker armjournals and bearings will be metered through the adjustable valve plug62 into the cup 64. When the engine is being operated at or near idlespeeds, the control tube 34-, the lever 33, the link 52, and the piston54 will be in the position shown in Figure 1. In this position of thepiston 54, the oil delivered to the cup 64 will be permitted to drainthrough the port 66 into the cylinder 56. When the governor-mountedaccelerator control lever 46 is actuated rapidly in a speedincreasingdirection, the throttle control linkages through the governor mechanism44 will tend to advance the link 40 and thereby rotate the throttlecontrol tube 34 in a clockwise fuel-increasing direction, as seen inFigure 1. This tendency to rotate the control tube 34 will be unretardedby the dashpot piston 54 as long as the port 66 is open; thereciprocation of the piston 54 merely forcing a portion of the entrappedfluid from the cylinder back into the cup 64- through the port 66.However, once the port 66 has been closed by the movement of the pistonto the position shown in Figure 3, the tendency to rotate the fuelcontrol tube in a fuel-increasing direction towards its full throttleposition will be retarded by the dashpotting action of the piston as itforces the fluid entrapped in the cylinder through the orifice 68. Thepressure of the entrapped fluid in the cylinder 56 will maintain theone-way check valve against its seat.

It will be noted that the position at which the port 66 opens or closesrelative to the position of the fuel injector racks 30 may be varied bythe adjustment of the throttle delay dashpot lever 48 on the controltube 34. The rapid initial fuel increase permitted by this feature ofthe dashpot mechanism 56 serves to insure the delivery of sufficientfuel to initiate the acceleration of the engine, and the subsequentperiod of retardation obtained by the use of the fluid dashpot mechanismprevents rotation of the injector rack control tube in a fuel-increasingdirection faster than the accelerating engine can efficiently utilizethe supplied fuel.

The yieldable link 4-0 between the governor and the control tubeassembly permits the accelerator control lever 46 on the engine governormechanism to be advanced rapidly to its maximum or Wide-open throttleposition by absorbing the delay in injector rack movement imposed by thedashpot mechanism 50. When the accelerator control lever 46 is returnedfrom its full throttle to idle position, this movement is positivelytransferred through the fuel control link 40 since the plunger will bein abutment with the bushing 76. This causes the control tube actuatinglever 38 to rotate the control tube in a counterclockwisefuel-decreasing direction. Such rotation of the control tube causes thethrottle delay lever and the link 52 to withdraw the piston toward theopen end of the dashpot cylinder. Air passing through the orifice 68 andthe one-way ball check valve 70 insures that the fuel-decreasingmovement of the injector control tube will not be retarded by thedashpot means.

While the foregoing description and figures have been confined to oneembodiment, it Will be apparent to those skilled in the art thatnumerous modifications may be made without departing from the spiritthereof. Accordingly, it is to be understood that the foregoing is to beconsidered as illustrative only and in no Way restrictive; referencebeing had to the appended claims to de termine the scope of theinvention.

I claim:

1. In a fuel injection type internal combustion engine, fuel controlmechanism including fuel injection means for each engine cylinder, amember movable between an idle speed position and a wide-open throttleposition and operable to control the fuel supply action of eachinjection means, governor means operable on said fuel control member toregulate the fuel supplying movement of said member to limit the maximumand minimum speeds of the engine, manually operable throttle controlmeans associated with said governor means and operably connected to saidmember for actuating said member between idle and wide-open, throttlepositions to control the speed'of the engine between saidgovernor-established speed limits, and dashpot means independent of saidgovernor means and operably connected'to said fuel control member toretard the movement-of said. fuel control member from its idle fuelsupply position to wide-open throttle position when said engine isoperating at a relatively low speed and said throttle control means isactuated from its idle position to its wide-open throttle position.

2. The combination as set forth in claim 1 in which said dashpot meansincludes a cylinder, a piston reciprocably mounted in said cylinder andoperably con nected to said member, a fluid supply cup mounted abovesaid cylinder and connectable thereto through a port controlled by saidpiston, means for supplying a portion of the engine lubricating oilsupply to said cup, said cylinder having a bleed orifice in the head endthereof for slowly bleeding oil entrapped in said cylinder when saidport is closed by said piston and permitting air to enter said cylinderwhen said piston is reciprocated in the opposite direction.

3. A fuel control mechanism for an internal combustion fuel injectiontype engine, comprising, in combination, fuel supply means, governormeans operably associated with said fuel supply means to limit themaximum and minimum speeds of the engine, manual control means operablyassociated with said fuel control means and said governor means andactuatable to control the speed of the engine between saidgovernor-established limit speeds, and means retarding the response ofsaid fuel supply means when said manual control means is rapidlyactuated in a speed-increasing direction.

4. The combination as set forth in claim 3 in which said last-mentionedmeans includes an expansible chamber fluid dashpot operably associatedwith said fuel supply means and comprising a cylinder, a pistonreciprocably mounted in said cylinder and operably connected to saidfuel supply means, fluid supply means connectable to said cylinderthrough a port intermediate the ends of said cylinder and controlled bysaid piston, said cylinder having a bleed orifice in the head endthereof for slowly bleeding oil entrapped in said cylinder when saidport is closed by said piston upon its actuation in a fuelincreasingdirection and supplying air to said cylinder when said piston isreciprocated in the opposite direction.

5. Control mechanism for an internal combustion engine including fuelsupply means, governor means operably associated with said fuel supplymeans to limit the maximum and minimum speeds of the engine, manualcontrol means operably associated with said fuel control means and saidgovernor means and actuatable between engine idle and maximum speedpositions to control the speed of the engine between saidgovernor-established limit speeds, and means regulating the response ofsaid fuel supply means when said manual control means is rapidlyactuated from its engine idle speed to engine maximum speed positionsand operable to provide for initial rapid fuel-increasing responsefollowed by a period of retarded fuel-supplying response to prevent anoversupply of fuel to said engine relative to the accelerating speed ofsaid engine.

6. The combination as set forth in claim 5 in which saidresponse-regulating means includes an expansible chamber fluid dashpotoperably associated with said fuel supply means and comprising acylinder, hydraulic fluid supply means mounted above said cylinder andconnectable thereto through a port intermediate the ends of saidcylinder, a piston reciprocably mounted in said cylinder and controllingsaid port, said cylinder having a bleed orifice in the head end thereofof a size such as to slowly bleed oil entrapped in said cylinder whensaid port is closed by reciprocation of said piston in a'fuelincreasingdirection and to permit the relatively unrestricted supply of air intosaid cylinder when said piston is reciprocated in the oppositedirection.

7. In an internal combustion engine, fuel control mechanism includingfuel injection means, a member movable between an idle speed positionand a Wide-open throttle position and operable to control the fuelsupplying action of said injecter means, governor means operable on saidfuel control member to regulate the fuel supplying movement of saidmember to limit the maximum and minimum speeds of the engine, throttlecontrol means associated with said governor means and operably connectedto said member for actuating said member between an idle and wide-openthrottle position to control the speed of the engine between saidgovernor-established speed limits, and dashpot means operableindependently of said governor means to retard the movement of said fuelcontrol member from its idle fuel supply position to wide-open throttleposition when said engine is operating at a relatively low speed.

8. The combination set forth in claim 7 in which said dashpot meanscomprises a cylinder, hydraulic fluid supply means connectable to saidcylinder through a port intermediate the ends of said cylinder, a pistonreciprocably mounted in said cylinder and controlling said port, saidpiston being operably connected to said movable member, said cylinderhaving a bleed orifice in the head end thereof of a size such as toslowly bleed hydraulic fluid entrapped in said cylinder when said portis closed by said piston as said member is moved in a fuelincreasingdirection and to permit the relatively unrestricted supply of air intosaid cylinder when said piston is reciprocated in the opposite directionas said member is moved in a fuel-decreasing direction.

9. Control mechanism for an engine, comprising, in combination, motivefluid supply controlling means, governor means operably associated withsaid fluid supply controlling means to limit the maximum and minimumspeeds of the engine, control means operably associated with said fluidsupply controlling means and said governor means and actuatable betweenminimum and maximum motive fluid-supplying settings to thereby controlthe speed of the engine between said governor-established limit speeds,and means regulating the response of said fluid supply controlling meanswhen said control means 6, is actuated from its minimum to maximum fluidsupplying settings, said response-regulating means including anexpansible chamber dashpot comprising a cylinder hydraulic fluid supplymeans connectable to said cylinder through a port intermediate theendsof saidcylinder, a

piston reciprocably mounted in said cylinder and controlling said port,said piston being operably connected to said control means, saidcylinder having a bleed orifice in the head and thereof of a size suchas to slowly bleed hydraulic fluid entrapped in said cylinder when saidport is closed by said piston as said control means is actuated in afluid-supply-increasing direction and. to permit relatively unrestrictedsupply of air into said cylinder when said piston is reciprocated in theopposite direction as said control means is actuated in afluidsupply-decreasing direction.

10. The combination set forth in claim 9 in which the operableconnection between said control means and said piston includes yieldablelinkage means permitting said control means to be rapidly actuated in amotive fluidsupply-increasing direction between its minimum and maximummotive fluid-supplying settings ahead of the regulated response of saidmotive fluid-supply-controlling means, said linkage means being operablewhen said control means is actuated in a motive fluid-supply-decreasingdirection to positively reciprocate said piston away from said cylinderhead.

11. A dashpot comprising a cylinder closed at one end and having a portopening intermediate the ends thereof, means for supplying hydraulicfluid to said port, a piston reciprocably mounted in said cylinder todefine an expansible chamber with the closed end thereof and controllingthe admission of hydraulic fluid into said expansible chamber throughsaid port, and means for slowly bleeding hydraulic fluid entrapped insaid expansible chamber by the closing of said port upon reciprocationof said piston toward the closed end of said cylinder thereby retardingfurther reciprocation of said piston toward the closed end of saidcylinder and for permitting the relatively unrestricted flow of air intosaid expansible chamber when said piston is reciprocated in the oppositedirection thereby permitting the relatively rapid and unrestrictedreturn of said piston in said opposite direction.

12. A dashpot mechanism comprising a cylinder closed at one end andhaving a port intermediate the ends thereof, hydraulic fluid supplymeans communicating with said port, a piston reciprocably mounted insaid cylinder and controlling said port, and said cylinder having ableed orifice therein interconnecting the interior of said cylinder withthe atmosphere outside said cylinder, said orifice being of a size suchas to slowly bleed hydraulic fluid entrapped in said cylinder when saidport is closed by the reciprocation of said piston toward said head endthereby retarding such further movement of said piston and means topermit the relatively unrestricted flow of air into said cylinder whensaid piston is reciprocated in the opposite direction thereby permittingrelatively unrestricted return of said piston in said oppositedirection.

13. An expansible chamber device including a cylinder closed at one endand having a port intermediate the ends thereof, a piston reciprocablymounted in said cylinder and adapted to be operably connected to anactuating member, a fluid supply cup mounted above said cylinder andconnectable thereto through said port, means for supplying hydraulicfluid to said cup, said port being controlled by the reciprocation ofsaid piston to regulate the flow of hydraulic fluid between said cup andsaid cylinder, said cylinder having a bleed orifice in the closed endthereof interconnecting the interior of said cylinder with theatmosphere outside said cylinder and being of a size to slowly bleedhydraulic fluid entrapped in said cylinder when said port is closed bythe reciprocation of said piston toward said head end, the location ofsaid port permitting the relatively unrestricted reciprocation of saidpiston toward said head until said port is closed, and means adapted topermit relatively unrestricted flow of air into said cylinder when saidpiston is reciprocated in the opposite direction.

14. The device as setforth in claim 13 and including a second orifice inthe head end of said cylinder and a one-Way valve controlling saidsecond orifice and operable to insure the flow of air into said cylinderand thereby the relatively unrestricted reciprocation of said '8 pistonwhen said piston is reciprocated in said opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS1,451,148 Floring Apr. 10, 1923 1,558,590 Carlson Oct. 27, 19251,714,160 Crowell 'et a1 May 21, 1929 2,571,571 Hanners et al Oct. 16,1951 2,708,921 Links May 24, 1955

